Raman Spectroscopic Analysis of Painted Medieval Burial Tombs From the Abbey Church in Bruges (Belgium)

ABSTRACT

In Flanders, painted burial tombs are a distinctive funerary practice between the 13th and 17th centuries, mainly located in Bruges and the Zwin region. These brick‐built graves, often single or double structured, were plastered and painted on the inside with religious depictions intended to guide the deceased in the afterlife. They were typically reserved for elite individuals such as clergy and nobility. Despite numerous archaeological finds, these tombs and their decorations remain under‐researched. To address this gap, the present study examines three painted tombs that were excavated at the former Eekhout Abbey in Bruges using Raman spectroscopy for pigment and material characterization. Initially, in situ measurements were performed with mobile Raman instrumentation to obtain a general overview of the materials used. When performing mobile Raman measurements, the red pigments were easily identified as haematite and vermilion. However, other coloured regions (e.g., yellow, black, grey and blue) proved to be more challenging to identify during the in situ measurements. Therefore, samples were collected for further analysis with a benchtop micro‐Raman system. This analysis identified carbon black and goethite for respectively the black‐ and yellow‐coloured regions and unexpectedly revealed the use of indigo as a blue pigment. Additionally, traces of an arsenic‐based pigment were detected, though it remains uncertain whether these were intentionally applied or are the result of contamination.